Systemic delivery has many shortcomings. When administered at higher levels and exposed to otherwise healthy tissue, such agents may harm healthy tissue and cause serious side effects. Furthermore, many agents are expensive. When these agents are delivered systemically, a caregiver must administer a higher dose in order to achieve a higher level of agent at the site of diseased tissue. As a result, much of the drug is wasted, which drives up the cost of the treatment. This waste is very significant given the high cost of pharmaceuticals.
Because of these shortcomings of systemic delivery, it is advantageous to preferentially treat the affected area. Many caregivers inject the agent directly to target tissue to preferentially treat an area of a patient's body. Internal delivery using injection requires penetration by a needle or similar device. Such penetration is intrusive, painful, often inaccurate, and does not evenly distribute the agent throughout the target area. To aggravate this situation, several injections may be required for relatively large target areas.
Transcutaneous delivery is one current technique to minimize systemic distribution of the agent. However, such delivery systems are limited to the application of an agent through the patient's skin or other surface tissue. Thus, transcutaneous delivery of an agent is inefficient especially if the target area is large and/or deep within the patient's body such as cervical and uterine tissue. Typically an amount of agent much larger than that required at the target site must be applied, which results in waste and is expensive.
The female reproductive tract is an example of a localized area within a women's body that is often treated by the systemic delivery of an agent or by direct injection of an agent. It is important to treat maladies that affect the reproductive tract, especially because there are many disorders that can threaten the life of a woman if not treated in their early stages. An example of such a disorder is human papillomavirus, which is a virus that can cause dysplasia and precursor changes to cervical malignancy, the second most common cancer in women. The longer these conditions go untreated, the more difficult they are to cure. As the disease progresses, it may need to be treated with major reconstructive surgery, increasingly dangerous agents such as cytotoxic agents or chemotherapeutic agents, and/or radiotherapy.
In addition to the delivery of an agent, a caregiver frequently needs to perform diagnostic or therapeutic procedures directly to the reproductive tract in order to effectively treat a patient. Examples of such procedures include hysteroscopy, tissue biopsy, and endometrial ablation. These procedures are presently done with general or regional anesthesia (e.g., epidural and spinal), both of which expose the patient to significant risks. Paracervical nerve blocks are also widely used for minor diagnostic procedures. The difficulty is that such nerve blocks expose the patient to the pain and trauma of needle injections. Furthermore, even if performed perfectly, paracervical nerve blocks do not result in adequate anesthesia of the fundus of the uterus. Moreover, nerve blocks do not prevent cramping pains induced by a foreign body in the uterus.
Therefore, a need exists for an agent delivery apparatus that provides uniform distribution of the agent to a localized area of internal bodily tissue. More particularly, a need exists for an apparatus that can deliver an agent to the reproductive tract without systemic administration of the agent and without the use of an injection directly into the tissue. There is also a need for a delivery device and method of anesthetizing tissue in the reproductive tract without using a general anesthetic or regional/local anesthesia. There is yet another need for the treatment of human papillomavirus in which an agent can be delivered deep into the basal cell layer of the cervical epithelium.